package com.wsoft.utils;

import org.apache.tomcat.util.codec.binary.Base64;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * 功能描述
 *
 * @author: juiet
 * @date: 2022年06月25日 10:11
 */
public class RsaUtil {
    /**
     * 加密算法RSA
     */
    public static final String KEY_ALGORITHM = "RSA";

    /**
     * 签名算法
     */
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    /**
     * 获取公钥的key
     */
    private static final String PUBLIC_KEY = "RSAPublicKey";

    /**
     * 获取私钥的key
     */
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    /**
     * RSA最大加密明文大小
     */
    private static final int MAX_ENCRYPT_BLOCK = 117;

    /**
     * RSA最大解密密文大小
     */
    private static final int MAX_DECRYPT_BLOCK = 128;

    /**
     * RSA 位数 如果采用2048 上面最大加密和最大解密则须填写:  245 256
     */
    private static final int INITIALIZE_LENGTH = 1024;

    /**
     * <p>
     * 生成密钥对(公钥和私钥)
     * </p>
     *
     * @return
     * @throws Exception
     */
    public static Map<String, Object> genKeyPair() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(INITIALIZE_LENGTH);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        Map<String, Object> keyMap = new HashMap<>(2);
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    /**
     * <p>
     * 用私钥对信息生成数字签名
     * </p>
     *
     * @param data
     *            已加密数据
     * @param privateKey
     *            私钥(BASE64编码)
     *
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = Base64.decodeBase64(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(privateK);
        signature.update(data);
        return Base64.encodeBase64String(signature.sign());
    }

    /**
     * <p>
     * 校验数字签名
     * </p>
     *
     * @param data
     *            已加密数据
     * @param publicKey
     *            公钥(BASE64编码)
     * @param sign
     *            数字签名
     *
     * @return
     * @throws Exception
     *
     */
    public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
        byte[] keyBytes = Base64.decodeBase64(publicKey);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PublicKey publicK = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(publicK);
        signature.update(data);
        return signature.verify(Base64.decodeBase64(sign));
    }

    /**
     * <P>
     * 私钥解密
     * </p>
     *
     * @param encryptedData
     *            已加密数据
     * @param privateKey
     *            私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception {
        byte[] keyBytes = Base64.decodeBase64(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 公钥解密
     * </p>
     *
     * @param encryptedData
     *            已加密数据
     * @param publicKey
     *            公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception {
        byte[] keyBytes = Base64.decodeBase64(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * 公钥加密
     * </p>
     *
     * @param data
     *            源数据
     * @param publicKey
     *            公钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {
        byte[] keyBytes = Base64.decodeBase64(publicKey);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicK = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * <p>
     * 私钥加密
     * </p>
     *
     * @param data
     *            源数据
     * @param privateKey
     *            私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {
        byte[] keyBytes = Base64.decodeBase64(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateK);
        int inputLen = data.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段加密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(data, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_ENCRYPT_BLOCK;
        }
        byte[] encryptedData = out.toByteArray();
        out.close();
        return encryptedData;
    }

    /**
     * <p>
     * 获取私钥
     * </p>
     *
     * @param keyMap
     *            密钥对
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return Base64.encodeBase64String(key.getEncoded());
    }

    /**
     * <p>
     * 获取公钥
     * </p>
     *
     * @param keyMap
     *            密钥对
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        return Base64.encodeBase64String(key.getEncoded());
    }

    /**
     * java端公钥加密
     */
    public static String encryptedDataOnJava(String data, String publicKey) {
        try {
            data = Base64.encodeBase64String(encryptByPublicKey(data.getBytes(), publicKey));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return data;
    }

    /**
     * java端私钥解密
     */
    public static String decryptDataOnJava(String data, String privateKey) {
        String temp = "";
        try {
            byte[] rs = Base64.decodeBase64(data);
            temp = new String(RsaUtil.decryptByPrivateKey(rs, privateKey), StandardCharsets.UTF_8);

        } catch (Exception e) {
            e.printStackTrace();
        }
        return temp;
    }

    public static void main(String[] args) throws Exception {
        String username = encryptedDataOnJava("admin", "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCFy6lsKBmYC8OPk8KXFwFsDgtDHNLozBcjItWzohgIFfF3KaO4jqMoXJeW4xY3L9Y9yxbNa0yhvrQ6t/Kv7tqK6qOpopgCbp9UH0vApQe4X1TsMP5Nl/5CLTjNGRP1+PRdsRypn8yR4wr2aheVJkSZggwSOfb8u5y1Q/keCVE/KQIDAQAB");
        System.out.println("secret = " + username);
        String nameInfo = decryptDataOnJava(username, "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");
        System.out.println("info = " + nameInfo);
        String password = encryptedDataOnJava("123456", "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCFy6lsKBmYC8OPk8KXFwFsDgtDHNLozBcjItWzohgIFfF3KaO4jqMoXJeW4xY3L9Y9yxbNa0yhvrQ6t/Kv7tqK6qOpopgCbp9UH0vApQe4X1TsMP5Nl/5CLTjNGRP1+PRdsRypn8yR4wr2aheVJkSZggwSOfb8u5y1Q/keCVE/KQIDAQAB");
        System.out.println("secret = " + password);
        String passInfo = decryptDataOnJava(password, "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");
        System.out.println("info = " + passInfo);


    }
}
